My drive slowly creeps back down ,, no leaks or bad lines ,, I'm thinking its time for a new trim pump ??? the leak is very slow but its driving me crazy. I could use a little advice Do i need to replace the pump, or just a part ? [1990 formula F242 LS 454 330 [performance bravo 1OL 435790 1.50 ] thanks

More than likely a leaking trim cylinder. If the seals on the ram piston leak then you will get this condition without any external leaks. Also could have a leaky check valve in the rams.

Great info Lofty ! How would you suggest I go about diagnosing which issue it might be? Also, I was told that it might be a ball that holds the pressure of the oil from the pump...does this sound possible? What part of the great bay are you from? I hail from ElCerrito.

typicly the pump bypass valvbe goes bad. the seala in the rams wouldnt be suspect , except because of the age of your boat. you can change the valving by removing the tank on the trim pump and addressing the faulty area, and purchasing a repair kit from a local merc part supplier.

good luck

Monstaaa from massapequa ... fantastic ! thanks for the great troubleshooting---

thanks don,

possibly the bypass valve too. If you block the ram lines and put a guage on the hp ("up" line) from the pump you can do a leak down on the pump. Shouldn't loose any press. You can also do a leak down on each ram.

We're in Pleasant Hill, just up off hwy 4 from El Cerrito. Shops in Martineze and soon moving to Bethel Isl. BI is cleaned up from what it was and is sporting a new and nicer development of Disco Bay.